Hollow Metal Frames

This graphic is good to get familiar with as it shows hollow metal frame terminology. You'll see these terms used frequently in most frame topics.

 

 

We stock standard jambs ready for welding to make a one piece unit and the knockdown drywall (KD DW) 3 piece type hollow metal frame. The KD DW frame is used for installation after the drywall is up. The welded type is used more often and can be installed in exterior walls or interior stud walls.

The hollow metal frames we offer include 18, 16 (the industry standard), 14, and 12 gauge frames for welding, which go into a masonry or a stud wall. These are available in jamb depths from 3" to 20". Anything with a jamb depth less than 4 3/4" will be a single rabbet frame. The knockdown drywall frames are available in 18, 16 (the industry standard), and 14 gauge. These frames are available in jamb depths from 4 3/4" to 14" as double rabbet and 3 1/4" to 4 3/8" as single rabbet.

Knockdown drywall frame: Although there are certainly variations, the most common stud walls, in our area, consist of 3 5/8" studs with either 1/2" drywall making a 4 5/8" wall, 5/8" drywall making a 4 7/8" wall, or 6" studs with 5/8" drywall making a 7 1/4" wall. The kd dw frame is meant to go over the drywall and comes in 3 separate pieces: the hinge jamb, strike jamb (two hinge jambs if it's a pair of doors), and the head. There are "compression anchors" (below right) in the top of each jamb and pre-drilled holes on each side of each jamb at the bottom as a base anchor, so there are no loose or separate anchors required with this frame as they are all part of the unit.

To install it you simply slide the head in place over the wall, install the hinge jamb by aligning the tabs in the top of the jamb with the slots in the head and pushing it over the wall, install the strike jamb (or other hinge jamb if it is a pair of doors) the same way as the hinge jamb (or other hinge jamb). Pull the head down tightly with the jambs and level by shimming at the base of the jambs if needed. Tighten the compression anchors, make sure the frame is square and level, and install sheet metal screws in the bottom holes. It is a good idea to cut a wood spreader bar to the exact door opening width and insert it at the bottom of the frame to keep the frame square during installation. Notice the double backbend on this type of frame...that's to help make it slide easier over the drywall. 

 

   

 

 

Welded frame: While the kd dw frame is used in interior stud walls, the welded frame can also be used in interior stud walls, but is also used in concrete block walls, or poured concrete walls. This type of frame is assembled in the shop, squared up, spreader bar welded in at the base, and the face joints welded and ground smooth.

It is installed in stud walls before the drywall goes up with either universal stud anchors (USA), steel stud anchors (SSA), or "Z" anchors. The universal stud anchors that are shown below clip inside the frame and have tabs on each side that bend around and wrap the stud. There are pre-drilled holes so you can screw the tabs to the stud. 6'8" and 7'0" frames are supplied with 6 anchors (3 per jamb) while 8'0" frames will have 8 (4 per jamb). 

                                                                                    

 

Below left is a steel stud anchor (SSA). This is similar to the USA, except you screw into the anchor from the back of the stud rather than wrapping the tabs around the stud like you do when you are using the USA's. Both USA and SSA are used in welded frames and both are installed in stud walls (metal or wood studs) before the drywall goes up. On the right is a Z-Clip anchor. This is welded into the back of the frame...the USA is almost always sent loose as a snap in anchor. The SSA is also sent loose as a snap in, but some specs call for welded in steel stud anchors so these are used both ways.

                          

 

If you are installing the frame in a poured concrete wall, it is usually set in place and the wall is poured around it. Base anchors come as standard in welded type hollow metal frames. These are welded or screwed into the bottom of both jambs. The base anchors have holes pre-drilled so you can fasten the frame to the floor.

 

In new block walls, the frame is fastened to the floor at the base anchors and either wire masonry anchors or T anchors are used. These are supplied either 6 or 8 to a frame and simply clip into the inside of the frame behind the single backbend and are laid in between the rows of block as the wall goes up. 

 

 

If you are installing the frame in an existing block wall, it will need to be "punch and dimpled". There is either 3 or 4 holes per jamb, 3/8" diameter, punched and countersunk in the jambs and either 4" or 5" (5" is the standard) redhead sleeve anchors supplied. You then set the frame in the opening, drill through the holes into the block with a 3/8" masonry bit, and screw the sleeve anchors in. There are anchors welded in the back for support of the frame and to keep the frame from expanding out (mushrooming) as you screw the redheads down. These anchors can be pipe sleeve anchors (left), butterfly anchors (center), or hat anchors (right). 

                     

 

Rough Opening Sizes

Rough opening size, kd dw frame: Take the nominal door width and add 1 1/2" and the nominal door height and add 3/4". Keep in mind that on a 3068 door, the nominal measurements are 3'0" x 6'8" while the actual measurements are 2' 11 3/4" x 6' 7 1/8". Using a 3068 door as an example, the rough opening size for a KD frame would be 3' 1 1/2" x 6' 8 3/4". This will allow the frame to partially wrap the wall at all 3 sides. You can increase the rough opening size a bit if needed but remember that the drywall must extend at least 1/2" into the frame at fire rated openings.

Rough opening size, kd dw frame cased open: Take the nominal door width and add 2" and the nominal door height and add 1". Keep in mind that on a 3070 door, the nominal measurements are 3'0" x 7'0" while the actual measurements are 2' 11 3/4" x 6' 11 1/8". Using a 3070 door as an example, the rough opening size for a KD cased open frame would be 38" x 85".

Rough opening size, welded frame: Take the nominal door width and add 4 1/4" and the nominal door height and add 2 1/4". Keep in mind that on a 3070 door, the nominal measurements are 3'0" x 7'0" while the actual measurements are 2' 11 3/4" x 6' 11 1/8". Using a 3070 door as an example, the rough opening size for a welded frame would be 3' 4 1/4" x 7' 2 1/4". Since the standard face on a hollow metal frame is 2", the outside dimensions of a 3070 welded frame will be 3'4" x 7'2" so this RO dimension will give you 1/4" of "play". If you are installing a welded frame into a fire rated stud wall, remember that the drywall will have to extend at least 1/2" into the frame so you can not simply butt the drywall up to the frame at fire rated openings. On non-rated openings you can run the drywall down to the frame or caulk the seam if it is going into block.

On a 3068 door, the nominal measurements are 3'0" x 6'8" while the actual measurements are 2' 11 3/4" x 6' 7 1/8". Using a 3068 door as an example, the rough opening size for a welded frame would be 3' 4 1/4" x 6' 10 1/4". Since the standard face on a hollow metal frame is 2", the outside dimensions of a 3068 welded frame will be 3'4" x 6'10" so this RO dimension will give you 1/4" of "play". If you are installing a welded frame into a fire rated stud wall, remember that the drywall will have to extend at least 1/2" into the frame so you can not simply butt the drywall up to the frame at fire rated openings. On non-rated openings you can run the drywall down to the frame or caulk the seam if it is going into block.